One interesting fanfiction could be about Harry's invisible friend helping him discover hidden secrets in Hogwarts. Maybe the friend has special powers that normal wizards don't, like being able to see through ancient magic barriers.
There could be a fanfiction where Harry's invisible friend is actually a manifestation of his own magical potential. So instead of being a separate entity, it represents the parts of his magic that he hasn't fully explored yet. This could lead to Harry learning new ways to use his magic, like being able to communicate with magical creatures in a different way or having an enhanced ability to perform spells without a wand.
One interesting plot could be Harry using an invisibility spell in a new way. For example, he might use it to spy on the Death Eaters' secret meetings without being detected. He could then use the information he gathers to outwit Voldemort. Another plot could involve Harry being invisible during a Quidditch match and using it to his team's advantage by confusing the opposing team. Or perhaps there's a fanfiction where an invisible Harry has to solve a mystery within Hogwarts that no one else can see is happening because he's the only one who can be undetected.
One interesting concept could be the idea of hidden magical abilities that are not explored in the original series. For example, characters might have the power to become truly invisible without the use of a cloak, and this could lead to all sorts of secret adventures.
One interesting story could be about a goblin who helps Harry in his quest for a powerful magical artifact. The goblin, with his deep knowledge of ancient magic and the secrets of Gringotts, provides crucial clues that lead Harry closer to his goal. This type of story often shows the unique relationship between humans and goblins in the Harry Potter universe.
One interesting story could be about a character who befriends a goblin in a way that changes the course of the wizard - goblin relations in the Harry Potter universe. Maybe they team up to solve a mystery that was long forgotten.
First, you need to understand the world of Harry Potter well. Know the rules of magic, the different characters' personalities, and the overall tone of the series. Then, create a unique and believable invisible friend. Give it a personality, motives, and a backstory.
One idea could be that Snape's invisible friend turns out to be a manifestation of his repressed childhood self. It could help him face his past traumas and insecurities.
One popular Harry Potter fanfiction is 'The Life and Times of Severus Snape'. It delves deep into Snape's backstory and his complex relationship with Lily Potter. Another is 'Harry Potter and the Methods of Rationality', which presents a more scientific and logical take on the wizarding world. There's also 'A Black Comedy' that offers a different perspective on the events and characters in the series, with a touch of dark humor.
A great plot could be that the goblin is a time - traveler. It has come from a future where Voldemort has won and is trying to change the past. The goblin teams up with Harry, using its unique goblin magic and knowledge of the future to give Harry an edge in the fight against the dark forces. They might have to travel to different magical locations and enlist the help of other magical creatures.
A possible plotline could be that Harry uses his invisibility to spy on Voldemort's followers and gather intelligence for the Order of the Phoenix. This would add an element of mystery and danger as he has to be extremely careful not to be detected.
One popular 'harry potter is invisible' fanfiction might be 'The Invisible Adventures of Harry Potter' where Harry discovers a spell that makes him invisible by accident and he has to navigate Hogwarts unseen. It's filled with humorous situations as he tries to avoid being detected by his friends and teachers.